Conventionally, an electric vehicle such as an electric automobile or a hybrid vehicle which travels by power of a rotary electric machine is provided with a power control unit (PCU) configured to control the rotary electric machine.
The power control unit includes an inverter which is connected between a battery and the rotary electric machine and converts a direct current voltage to an alternating voltage or an alternating current voltage to a direct current voltage.
In a conventional electric vehicle, a case accommodating the rotary electric machine and the power control unit are separately attached to a vehicle frame member, and the power control unit is connected to the rotary electric machine via a three-phase cable. Therefore, an attaching frame for the power control unit may be required, and also a noise may be generated from the three-phase cable.
WO 2016/121032 discloses a rotary electric machine unit in which a power control unit is directly mounted on a case accommodating a rotary electric machine. According to the rotary electric machine unit, since an attaching frame for the power control unit or a three-phase cable is not necessary, weight and cost of a vehicle body can be reduced, and also the occurrence of noise can be reduced.
However, in the rotary electric machine unit in which the power control unit is directly mounted on the case accommodating the rotary electric machine, radiation sound of the rotary electric machine may resonate between an upper surface of the case and a bottom surface of the power control unit, so that the radiation sound may be amplified.